1. Field of the Invention
The invention relates to an internal mixer, comprising a housing, which encloses a mixing chamber, and which has end walls facing each other; at least one rotor, which is disposed in the mixing chamber, which has mixing devices, which defines a gap towards the end wall, and which has journals that pass through the end walls out of the mixing chamber, forming an annular gap that is connected to the gap; and bearing arrangements, which are disposed outside the mixing chamber, which have a bearing housing, and in each of which a journal is run on a bearing.
2. Background Art
Internal mixers of the generic type have been disclosed by prior public use; they comprise bearing blocks which are separate from the housing of the internal mixer and spaced from the end walls of the housing. Disposed between the journals of the shaft and the end walls are seals in the form of stuffing box packings or the like. Internal mixers of the generic type primarily serve to knead rubber together with carbon black and other fillers and loading agents. In particular particles of carbon black will exit as dirt through the seals. These dirt particles can be impasted and agglutinated in the vicinity of the seal by the supply of oil or other suitable bonding agents. A drawback of this familiar design resides in that the bearings are comparatively remote from the housing, which renders the rotors comparatively long. This leads to unfavorable elastic curves of the rotors on the one hand and to an increase in diameter and weight of the rotors on the other, requiring greater stability of the bearings. Furthermore, cleaning between the bearing blocks and the seals is rather complicated, the bearing blocks being not sufficiently remote from the end walls for easy access to the interstice and the sealing area.
It is an object of the invention to embody the internal mixer of the generic type in such a way that bedding the rotors is simplified and sealing is improved.
According to the invention, this object is attained by the features which consist in that the bearing housings are disposed on the end walls; and in that allocated to each bearing housing is at least one dirt-particle outlet which is connected to the annular gap and bridges the bearing. These measures ensure that no bearing blocks which are separate from the housing are necessary, but that the bearing housings are mounted directly on the respective end wall. This leads to a reduction in length of the rotors, in particular of the journals of the shaft, and thus to improvement of the elastic curve of the rotors. The diameter of the rotors can be reduced. Any complicated jobs of cleaning between the bearing block and the end wall or the seal can be dropped, because the dirt particles are removed outwards past the bearing.
Further features, advantages and details of the invention will become apparent from the ensuing description of three exemplary embodiments, taken in conjunction with the drawing.